What is a jitter buffer used for?

Telecom expert Matt Brunk explains the uses for a jitter buffer on a VoIP network and the importance of configuring it properly.

Can you explain what a jitter buffer is used for and which Voice over Internet Protocol (VoIP) technology typically includes jitter buffers?

Ask the Expert

Do you have a question for Matt Brunk or any of our other experts? Ask your enterprise-specific questions today! (All questions are treated as anonymous.)

WhatIs defines jitter as the variation in the time between packets arriving on a VoIP system. These variations can be caused by network congestion, timing drift or route changes. Jitter buffers are used to counter delay or latency, dropped packets, and jitter introduced by queuing. They temporarily store arriving packets to minimize jitter and discard packets that arrive too late.

However, jitter buffers must be correctly configured to be effective. A jitter buffer configuration is typically 30 milliseconds  to 50 ms. Adaptive jitter buffers, which can adjust their size dynamically, can be configured to up to 100 ms to 200 ms. Be sure to configure your jitter buffer correctly because you don't want the solution to become the problem.

If a jitter buffer is too small, an excessive number of packets may be discarded. This can lead to call quality degradation. Alternatively, a jitter buffer that's too large can result in conversational difficulty caused by additional delay and echo.

To solve these issues, you can adjust the jitter buffer's configuration levels. You can also use a jitter analyzer such as an oscilloscope to isolate the source of the jitter and eliminate it.

Learn more about jitter buffers:

  • A case of the jitters: Learn how to monitor and analyze the effectiveness of the jitter buffer in your VoIP system with a jitter buffer emulator.
  • Manage call quality by checking packet loss: Learn why measuring packets discarded by jitter buffers is necessary for managing call quality.
  • Determining call quality types: Learn why it's important to focus on jitter buffer discards when measuring VoIP listener call quality.

Dig Deeper on VoIP and IP telephony